This invention relates to methods of and a tool for attaching to an element, and particularly relates to methods of and a tool for attaching to an insert to facilitate assembly of the insert with a support structure.
Spark plugs are a crucial element in the operation of internal combustion engines. Typically, such engines include an engine block having specifically located threaded ports for receipt of a correspondingly threaded portion of the spark plugs. During the life of the engine, the spark plugs may be removed from the respective ports for testing, cleaning and/or replacement. Frequent removal, reinsertion and/or replacement of the spark plugs results in damage to and/or wear of the threads in the ports of the engine block to the extent that the ports can no longer support the spark plugs, or can not accept the spark plugs in the firm manner, necessary for the efficient and effective operation of the engine. In such instances, the ports must be revitalized for continued use of the engine.
In one technique used to revitalize the damaged or worn threads of the spark plug ports, the port is bored initially to form an oversize, smooth-walled passage about the centerline of the existing port, whereby the original defective threads are completely removed. The oversize passage is then tapped to form threads of a prescribed size. A commercially available insert, having threads on the outer surface consistent with the prescribed size, and threads on the inner surface consistent with the standard spark plug threads, is installed in the threaded oversize passage. The spark plug can now be assembled with the threaded inner surface of the insert which forms a new or revitalized port.
The insert could be a bushing, referred to herein as a "bushing insert," having an axial passage therethrough, with outer threads formed on an outer surface thereof in an axial direction, and inner threads formed on an inner surface thereof in the axial direction.
The insert could also be made from a preformed metal wire, typically formed with a diamond cross section, which is wound to form a helical coil having successive convolutions. The helical coil is referred to herein as a "coil insert." The coil insert is wound in such a manner that outer and inner threads are formed by sharp, generally "V" shaped portions on opposite sides of the diamond cross section on the outer and inner surfaces, respectively, of the insert.
The size of the outer threads of the bushing insert and the coil insert are consistent with the size of the threads of the oversize passage, and the size of the inner threads of the bushing insert and the coil insert are consistent with the size of the threads typically formed on a portion of the outer surface of the spark plug.
In the past, the bushing and coil inserts have been assembled by hand, or by use of a spark plug serving as an insertion tool. When using the spark plug for assembling the bushing inserts or the coil inserts, the spark plug is threadedly assembled with the inner threads of the insert to form an insert-spark plug assembly. The assembly is then manipulated to position the insert into the oversize threaded passage where the outer threads of the insert are threadedly assembled with the threads of the oversize passage. While either technique is tedious at best, the assembly process is further compounded by the fact that many spark plug ports are located in deeply recessed portions of the outer surface of the engine block due to the shape of the block.
A compound, such as high temperature RTV silicone, is placed on the outer threads of the insert prior to its assembly with the oversize passage. When the silicone cures, a sealing and locking bond is formed between the threads of the oversize passage and the outer-surface threads of the insert. During the curing period, the spark plug used for assembling the insert must remain in place until the silicone cures, which delays the process of revitalizing the ports of the block.
Thus, there is a need for a tool which will attach to the insert to facilitate the handling of the insert as desired. Further, there is a need for a tool which will attach to the insert to facilitate the rapid and effective assembly of outer threads of the insert within a passage having threads of a prescribed size, even though the passage is located at the base of a deep recess. Also, there is a need for a tool which can be detached from attachment with the insert immediately upon assembly of the insert within the passage notwithstanding the presence of an uncured locking and sealing compound between the threads of the passage and the outer threads of the insert.
There is also a need for methods of attaching to the insert for the handling thereof, for inserting the insert into the threaded passage, and for detaching from the insert without movement of the assembled insert.